Process of preventing oxidation of molten metals.



Nu. 698,769. Patented Apr. 29, |902.

, J. H. WALKER. f Panoz-:ss oF Pn'- vEN`T|NG oxmATmN oF M'OALTE'N METALS.

(Application mea July 17, 1899.)

(No Model.)

JAMES H. WALKER, OF MILVAUKEE, IVISOONSIN, ASSIGNOR OF ONE-HALF TO ELIAS H. BOTTUM, OF MILWAUKEE, WISCONSIN.

PROCESS OF PREVENTING OXIDATION OF MOLTEN METALS.

SPEC-IFIGATION forming' part of Letters Patent No. 698,769, dated April 29, 1902.

Application led July 17, 1899. Serial No. 724,073. (N Specimens.)

To @ZZ whom it may concern: E, which is formed with a central opening e Be it known that I, JAMES H. WALKER, a forthe escape ot' the'produ'cts of combustion, citizen of the United States, residing'at Milas hereinafter explained. Each of the side waukee, in the county of Milwaukee and State walls of the crucible is formed near its upper 55 of Wisconsin, have invented certain new and edge or above the level to which the molten useful Improvements in Processes of Preventmetal is intended to rise with a horizontal seing Oxidation of Molten Metals, of which the ries of openings d. following is a specification, reference being The space in the furnace below the crucihad to the accompanying drawings, forming ble is divided by a longitudinal partition F 6o 1o a part thereof. Y into twolongitudinal fluesf, which communi- The main object of my invention is to precate at opposite ends of the furnace and at vent the oxidation of molten metals, and thus one end of each iiue through vertical passages 'avoid waste of material and loss of time in g with longitudinal side flues h, extending melting metals and in usingthe molten metal. from one end of the crucible to the other, in 65 I5 It consists in the process hereinafter parcommunication with the openings d.

- ticnlarly described, and pointed out in the IIare gas-burners,whichprojectintoopenclaims. ings in the end walls of the furnace and are In the accompanying drawings, illustrating constructedand arranged to direct their suitable apparatus for carrying out the procnames in opposite courses through the flues 7o zo ess, like letters designate the same parts in ff underneath and in contact with the meltthe several figures. ing-pot. The bottom ofthe melting-pot is Figure l is a plan View of a furnace for preferably curved downward toward the midmelting, metals and preventing oxidation die from end to end, so as to subject itto the thereof according to my process, the greater Vdirect action of the flames issuing from the 754 portion of the melting-pot or crucible being burners and to absorb the greater portion of broken away to disclose the arrangement of the heat thus produced where it will be most the furnace-fines. Fig. 2 is a longitudinal effective for melt-ingthe contents of the meltsection of the furnace on the line 2 2, Fig. l. ing-pot, as well as to facilitate dipping out Fig. 3 is a similar section showing the furthe molten metal with a ladle.; 8o 3o nace without the crucible or melting-pot; and In carrying out my process by the apparatus Fig. 4 is a cross-section on the line 4c 4, Fig. 1. hereinbefore described the metal to be melted For the purpose of illustration I have shown is placed in the pot or crucible D and the cover v a furnace adapted to use gas as fuel for melt- E is placed thereon, as shown inFigs. 2 and 4. ing metal; but the process may be practiced TheburnersI being lighted direct their flames 85 with apparatus adapted to use other kinds of from opposite ends of the furnace through the fuel. lues ff underneath and against, the bottom of A designates a furnace, the bottom and side the melting-pot. At `the ends ofthe fines f walls ct ct of which are constructed of fireopposite the burners I the flames and heated brick or other suitable refractory material inproducts of combustion pass through the ver- 9o 4o closed and protected on the outside bya sheettical openings or passages ginto the return metal casing Z) and provided on the topwith side flues h, where they act on the sides of a plate c, havingan opening therein to receive the melting-pot and assist in melting the the crucible or melting-pot. metal 'contained therein. From the lines h D is the crucible or melting-pot, which may the gaseous products of combustion resulting 9"5 be made of cast-iron and is preferably of quad' from the complete combustion of the gas or rangular form in horizontal section. It is fuel which is employed to melt the metals made to fit closely inside of the four walls o, and from which the greater part of the heat of the furnace, as shown in Figs. 2 and 4, and has been absorbed by the walls of the melthas around its upper edge an outwardly-proing-pot pass through the openings d'into the roo 5o jecting iiange d, which rests upon the top upper part of said pot, whence they escape plate c. It is provided with a suitable cover through the opening e in its cover. These .structed and arranged with respect to the gaseous products, which contain little or no I free oxygen that will affect the molten metal, being directed by the openings d horizontally toward the longitudinal center of the meltingpot, envelop or cover the contents of the melting-pot,and thus prevent access ofair thereto and consequent oxidation. Whenthe metal is melted, the cover E may be removed and the molten metal dipped with ladles from the open pot without exposing such metal to the oxidizing effect of the air, the gases issuing from the openings in the sides of the pot when the cover E is removed maintaining a nonoxidiziug envelop and preventing the air from coming in contact with the metal, at the same time affording free access to the contents of the pot for the purpose of dipping it out with a ladle as it is needed.

When a body of metal has once been melted, the melting-pot maybe replenished from time to time, so as to fu rnish a continuous supply of molten metal as often asit may be needcd,and the necessity pf frequently removing the scum or dross produced by constant exposure to air and the resulti ng loss of time and waste of heat and metal incident to the employment of the usual methods and apparatus for melting metals are avoided without in any wise obstructing access to the molten metal-and its removal from the melting-pot whenever it is required.l

The furnace and its fines should be so concrucible or melting-pot that the metal will be melted by the direct application of the heat to the Walls of the melting-pot, and combustion of the fuel will be practically complete before the resulting gases are allowed to pass into the melting-pot or over the metal coutained` therein. In this Way no free oxygen or air is permitted to come into contact with the melting or molten metal.

The arrangement of the burners I I at opposite ends of'the furnace,l in connection-with the construction and arrangement of the fines, distributes the heat to the best advantage and prevents the unequal expansion and contraction that would otherwise tend to crack or injure the melting-pot and furnace. Vthen ordinary commercial gas is used, the burners may be made of iron or other metals; but when gas (technically known as producergas) distilled from solid fuels is used the burners may be built into and become a part of the fire-brick lining of the furnace containing the melting-pot or crucible, in direct connection with which furnace the gas-generator is placed.

The perforated cover E is for the purpose of retaining the heat in the Crucible during the operation of melting and also of holding the gaseous products of combustion in close contact with the surface of the metal during the melting period, particularly in making alloys of metals having different meltingpoints, so as to prevent the oxidation of the constituent metal or metals which has a lower melting-point than that of the resulting alloy.

Apparatus of various kinds adapted to use different kinds of fuel and to melt different metals for various purposes may be used in carrying lout the process in accordance with my invention and within the scope of the following claims.

I claim- 1. The process of preventing oxidation of molten metal in open crucibles or meltingpots, consisting i'n directing the non-oxidizing gases which are produced by the complete combustion of the fuel employed to melt the metal and from which heat has been absorbed, over the surface of the molten metal so as to exclude the air therefrom, Without interfering with the removal of the molten metal when the crucibles or pots are open,substantially as and for the purposes set forth.

2. The process of melting metal and preventing oxidation thereof,consisting in applying the heat, produced by the combustion of the fuel employed, directly to the bottom and sides of the crucible or pot containing the metal to be melted, and directing the nonoxidizing gaseous products of complete combustion, from which heat has been absorbed to melt the metal, horizontally over the surface of the metal contained in said crucible or pot so as to produce and maintain an air-excluding gaseous covering or envelop over the metal While it is being melted and is in a molten condition, and permit of removing the molten metal when the Crucible or pot is open, without allowing access of air to the metal containedin said crucible or pot,substantial1y as and for the purposes set forth.

3. The process of melting metal and preventing oXidation thereof, consisting in conducting the gaseous products of the fuel, employed to melt the metal, in a sinuous course along and in contact with the walls of the crucible or melting-pot until all or the greater part of the effective heat for melting has been absorbed, and in then directing the incombustible gases over the surface of the metal so as to prevent access of air thereto, and permit of removing the molten metal from the Crucible or pot without allowing air to come in contact with the metal contained in said Crucible or pot, substantially as and for the purposes set forth.

In witness whereof I hereto affix my signature in presence of two witnesses.

JAMES H. WALKER.

Vvlituesses:

CHAS. L. Goss, D. A. KELLEY.

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